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Host-dependent Induction of Transient Antibiotic Resistance: A Prelude to Treatment Failure.

Kubicek-Sutherland JZ, Heithoff DM, Ersoy SC, Shimp WR, House JK, Marth JD, Smith JW, Mahan MJ - EBioMedicine (2015)

Bottom Line: This mechanism has escaped prior detection because it is reversible and operates within a subset of host tissues and cells.Bacterial pathogens are thereby protected while their survival promotes the emergence of permanent drug resistance.This host-dependent mechanism of transient antibiotic resistance is applicable to multiple pathogens and has implications for the development of more effective antimicrobial therapies.

View Article: PubMed Central - PubMed

Affiliation: Dept. of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA.

ABSTRACT
Current antibiotic testing does not include the potential influence of host cell environment on microbial susceptibility and antibiotic resistance, hindering appropriate therapeutic intervention. We devised a strategy to identify the presence of host-pathogen interactions that alter antibiotic efficacy in vivo. Our findings revealed a bacterial mechanism that promotes antibiotic resistance in vivo at concentrations of drug that far exceed dosages determined by standardized antimicrobial testing. This mechanism has escaped prior detection because it is reversible and operates within a subset of host tissues and cells. Bacterial pathogens are thereby protected while their survival promotes the emergence of permanent drug resistance. This host-dependent mechanism of transient antibiotic resistance is applicable to multiple pathogens and has implications for the development of more effective antimicrobial therapies.

No MeSH data available.


Related in: MedlinePlus

The role of the environment (Fe3 +) in microbial susceptibility to antibiotics. (A) pmrAB and phoPQ  (pmrA601::Tn10d-Kn, phoP102::Tn10d-Cm) and constitutively active mutations (pmrA505, phoQ24) were introduced into S. Typhimurium 14028. Bacteria were grown in either LPM or MHB at pH 5.5 or pH 7 and MIC values were determined in the same medium from at least three independent determinations. (B) Bacteria were grown in LPM pH 5.5 medium in the presence and absence of 100 μM FeSO4, or in the presence of a complementing plasmid containing wild-type sequences of the indicated mutation. * denotes no growth in the presence of 100 μM FeSO4 due to iron toxicity. GI; gastrointestinal. (03)-1516 (horse non-GI) pmrABP1 -72C>T, pmrB H152Y; F2 (human feces) pmrABP1 -72C>T, pmrB H152Y; F1 (human feces) pmrABP2 1599G>A; F13 (human feces) pmrABP2 1408T>C, pmrC E415Q; F7 (human feces) phoQ P83L. Both B10 (human blood) and var. 5 (04)-9639 (cow GI) strains were complemented to TIVAR + with recombinant PmrD + sequences (Roland et al., 1994); corresponding mutations were not found in pmrD, phoPQ, or pmrCAB, suggesting parental mutation(s) are within other genes in the PhoPQ/PmrAB pathway. (C) Bacteria were grown in MHB pH 7.2 (unbuffered) or MHB pH 5.5 media in the presence and absence of 100 μM FeSO4, and the polymyxin B MIC was determined in the same medium from at least three independent determinations.
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f0020: The role of the environment (Fe3 +) in microbial susceptibility to antibiotics. (A) pmrAB and phoPQ (pmrA601::Tn10d-Kn, phoP102::Tn10d-Cm) and constitutively active mutations (pmrA505, phoQ24) were introduced into S. Typhimurium 14028. Bacteria were grown in either LPM or MHB at pH 5.5 or pH 7 and MIC values were determined in the same medium from at least three independent determinations. (B) Bacteria were grown in LPM pH 5.5 medium in the presence and absence of 100 μM FeSO4, or in the presence of a complementing plasmid containing wild-type sequences of the indicated mutation. * denotes no growth in the presence of 100 μM FeSO4 due to iron toxicity. GI; gastrointestinal. (03)-1516 (horse non-GI) pmrABP1 -72C>T, pmrB H152Y; F2 (human feces) pmrABP1 -72C>T, pmrB H152Y; F1 (human feces) pmrABP2 1599G>A; F13 (human feces) pmrABP2 1408T>C, pmrC E415Q; F7 (human feces) phoQ P83L. Both B10 (human blood) and var. 5 (04)-9639 (cow GI) strains were complemented to TIVAR + with recombinant PmrD + sequences (Roland et al., 1994); corresponding mutations were not found in pmrD, phoPQ, or pmrCAB, suggesting parental mutation(s) are within other genes in the PhoPQ/PmrAB pathway. (C) Bacteria were grown in MHB pH 7.2 (unbuffered) or MHB pH 5.5 media in the presence and absence of 100 μM FeSO4, and the polymyxin B MIC was determined in the same medium from at least three independent determinations.

Mentions: Since the PhoPQ/PmrAB regulons contribute to resistance to cationic peptides via LPS remodeling of Gram-negative membranes (Chen and Groisman, 2013; Gunn, 2008), we tested whether these regulatory functions were required for the TIVAR phenotype. Introduction of pmrA and/or phoP mutations into TIVAR + S. Typhimurium abrogated PMB resistance under inducing and non-inducing conditions; whereas introduction of constitutively active mutations in pmrA or phoQ (Groisman et al., 1997; Gunn and Miller, 1996; Roland et al., 1993; Tamayo et al., 2005) resulted in high-level PMB resistance under non-inducing conditions (Fig. 3A). None of these mutations affected the induction of trimethoprim or ciprofloxacin resistance, suggesting that the host microenvironment may influence microbial susceptibility through multiple regulatory pathways, each operating in antibiotic-specific fashion.


Host-dependent Induction of Transient Antibiotic Resistance: A Prelude to Treatment Failure.

Kubicek-Sutherland JZ, Heithoff DM, Ersoy SC, Shimp WR, House JK, Marth JD, Smith JW, Mahan MJ - EBioMedicine (2015)

The role of the environment (Fe3 +) in microbial susceptibility to antibiotics. (A) pmrAB and phoPQ  (pmrA601::Tn10d-Kn, phoP102::Tn10d-Cm) and constitutively active mutations (pmrA505, phoQ24) were introduced into S. Typhimurium 14028. Bacteria were grown in either LPM or MHB at pH 5.5 or pH 7 and MIC values were determined in the same medium from at least three independent determinations. (B) Bacteria were grown in LPM pH 5.5 medium in the presence and absence of 100 μM FeSO4, or in the presence of a complementing plasmid containing wild-type sequences of the indicated mutation. * denotes no growth in the presence of 100 μM FeSO4 due to iron toxicity. GI; gastrointestinal. (03)-1516 (horse non-GI) pmrABP1 -72C>T, pmrB H152Y; F2 (human feces) pmrABP1 -72C>T, pmrB H152Y; F1 (human feces) pmrABP2 1599G>A; F13 (human feces) pmrABP2 1408T>C, pmrC E415Q; F7 (human feces) phoQ P83L. Both B10 (human blood) and var. 5 (04)-9639 (cow GI) strains were complemented to TIVAR + with recombinant PmrD + sequences (Roland et al., 1994); corresponding mutations were not found in pmrD, phoPQ, or pmrCAB, suggesting parental mutation(s) are within other genes in the PhoPQ/PmrAB pathway. (C) Bacteria were grown in MHB pH 7.2 (unbuffered) or MHB pH 5.5 media in the presence and absence of 100 μM FeSO4, and the polymyxin B MIC was determined in the same medium from at least three independent determinations.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4588393&req=5

f0020: The role of the environment (Fe3 +) in microbial susceptibility to antibiotics. (A) pmrAB and phoPQ (pmrA601::Tn10d-Kn, phoP102::Tn10d-Cm) and constitutively active mutations (pmrA505, phoQ24) were introduced into S. Typhimurium 14028. Bacteria were grown in either LPM or MHB at pH 5.5 or pH 7 and MIC values were determined in the same medium from at least three independent determinations. (B) Bacteria were grown in LPM pH 5.5 medium in the presence and absence of 100 μM FeSO4, or in the presence of a complementing plasmid containing wild-type sequences of the indicated mutation. * denotes no growth in the presence of 100 μM FeSO4 due to iron toxicity. GI; gastrointestinal. (03)-1516 (horse non-GI) pmrABP1 -72C>T, pmrB H152Y; F2 (human feces) pmrABP1 -72C>T, pmrB H152Y; F1 (human feces) pmrABP2 1599G>A; F13 (human feces) pmrABP2 1408T>C, pmrC E415Q; F7 (human feces) phoQ P83L. Both B10 (human blood) and var. 5 (04)-9639 (cow GI) strains were complemented to TIVAR + with recombinant PmrD + sequences (Roland et al., 1994); corresponding mutations were not found in pmrD, phoPQ, or pmrCAB, suggesting parental mutation(s) are within other genes in the PhoPQ/PmrAB pathway. (C) Bacteria were grown in MHB pH 7.2 (unbuffered) or MHB pH 5.5 media in the presence and absence of 100 μM FeSO4, and the polymyxin B MIC was determined in the same medium from at least three independent determinations.
Mentions: Since the PhoPQ/PmrAB regulons contribute to resistance to cationic peptides via LPS remodeling of Gram-negative membranes (Chen and Groisman, 2013; Gunn, 2008), we tested whether these regulatory functions were required for the TIVAR phenotype. Introduction of pmrA and/or phoP mutations into TIVAR + S. Typhimurium abrogated PMB resistance under inducing and non-inducing conditions; whereas introduction of constitutively active mutations in pmrA or phoQ (Groisman et al., 1997; Gunn and Miller, 1996; Roland et al., 1993; Tamayo et al., 2005) resulted in high-level PMB resistance under non-inducing conditions (Fig. 3A). None of these mutations affected the induction of trimethoprim or ciprofloxacin resistance, suggesting that the host microenvironment may influence microbial susceptibility through multiple regulatory pathways, each operating in antibiotic-specific fashion.

Bottom Line: This mechanism has escaped prior detection because it is reversible and operates within a subset of host tissues and cells.Bacterial pathogens are thereby protected while their survival promotes the emergence of permanent drug resistance.This host-dependent mechanism of transient antibiotic resistance is applicable to multiple pathogens and has implications for the development of more effective antimicrobial therapies.

View Article: PubMed Central - PubMed

Affiliation: Dept. of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA.

ABSTRACT
Current antibiotic testing does not include the potential influence of host cell environment on microbial susceptibility and antibiotic resistance, hindering appropriate therapeutic intervention. We devised a strategy to identify the presence of host-pathogen interactions that alter antibiotic efficacy in vivo. Our findings revealed a bacterial mechanism that promotes antibiotic resistance in vivo at concentrations of drug that far exceed dosages determined by standardized antimicrobial testing. This mechanism has escaped prior detection because it is reversible and operates within a subset of host tissues and cells. Bacterial pathogens are thereby protected while their survival promotes the emergence of permanent drug resistance. This host-dependent mechanism of transient antibiotic resistance is applicable to multiple pathogens and has implications for the development of more effective antimicrobial therapies.

No MeSH data available.


Related in: MedlinePlus